Identification/Description: Eight legs; stinger at end of
telson, Kaufman, p. 24. “The scorpion's body has two parts, a cephalothorax
which contains the prosoma, or head; and the abdomen. The cephalothorax is
covered by the carapace, a hard bony or chitinous outer covering. The carapace
usually suports [sic] a pair of median eyes at the top center. Two to five
pairs of lateral eyes are found at the front corners of the carapace, though a
few cave and montane forest litter-dwelling scorpions are eyeless. Chelicerae,
the scorpion's mouthparts, and a pair of pedipalps, or claws used for prey
capture and mating complete the head anatomy. The pedipalps are covered with
trichobothria, sensory setae, that sense air-borne vibrations. The abdomen is
made up of the mesosoma, the main body, and the metasoma, the tail. The
mesosoma, protected by bony armour, contains the lungs, digestive organs and
sexual organs, as well as bearing 4 pairs of walking legs and the pectines. The
tips of the legs have small organs that detect vibrations in the ground. The
pectines are feathery sensory organs which hang beneath the abdomen and trail
on the ground. They are coated by chemosensors that provide detection of minute
chemical signals that are thought to alert the scorpions to the approach of
prey and also to be of use in mating behavior. The respiratory structure, known
as "book lungs," are spiracles that open into the scorpion's body.
The surfaces of the legs, pedipalps, and body are also covered with thicker
hairs that are sensitive to direct touch. The metasoma curves up and ends in
the telson, which bears the bulbous vesicle containing the venom glands and a
sharp, curved aculeus which delivers the venom,” according to “Scorpions” at DesertsUSA.com.Real advances in systematics will come with the
adoption of the scanning electron microscope (SEM), according to Brewer (2007).

Length: 2-3 inches
at adulthood; average 6 centimeters.

Metamorphosis/Immature
Stages:Simple/gradual.“Females give live birth, and the babies ride
on mom’s back [for 5-15 days] until their first molt,” Kaufman, p. 24 and “The
Best Control.” The fist instar, between 7-17 days, does not fluoresce (Polis
and Mohnac, 1990).Gestation five months
to a year with up to thirty young at birth, which will then molt six or seven
times.Parthenogenesis possible.

Life Cycle:“Males and females find each other by
vibration, scent and touch,” according to ScorpionFacts.Three-to-four/seven years to maturity.They can live 3, 15-25 years, according to
“The Best Control for Scorpions.”

Food: Waiting in
ambush due to their poor eyesight, they eat “all types of insects, spiders,
centipedes, and other scorpions.They
capture their prey with their pedipalps, paralyzing them with their venom as
well if necessary. The immobilized prey is then subjected to an acid spray that
dissolves the tissues, allowing the scorpion to suck up the remains,” according
to DesertsUSA. According to Insects of the LA Basin (1993), they prefer
soft-bodied insects [including] …beetles, cockroaches, crickets, centipedes,
spiders, sun spiders, and other ground dwellers.”

Prevenom
(containing less protein but more K+ ions) to induce pain has been identified
by Ahmet B. Inceoglu (UC Davis, PhD, 2002).Neurotoxins (up to 20 or more; today, more
than 200 known) in the venom contain about 60-70 amino acids cross-linked by
four disulfide bridges (see Suddath et al., 1982).Extremely low metabolism; supposedly can
withstand starvation for 4-5 months, according to “Safe Controls” at Best
Solutions.

Lethal Food Plants:“Around 300 BC, Theophrastus, in book 9 of
his Enquiry to Plants, noted that wolfsbane, or scorpion plant (Aconitum
anthora) kills scorpions if it is shredded over them. Pliny in book 20 of his Natural History,
written in the first century A.D. advised that a mallow leaf (Malva) placed
on a scorpion paralyzes it," according to “Safe Controls for Scorpions.”

Behavior: Nocturnal; navigation by starlight; sluggish
at temperatures below 70° F and avoid temperatures over 100 F°, according to
“The Best Control.”24-36 hour courting/mating
dance ritual with pedipalps.Although
they can see in the UV range and controlled by the SWS1 gene, prey location is accomplished
by non-visual cues (i.e., sound waves in sand): “One sensor, called the
basitarsal slit sensillum, detects the surface wave propagated by sand, while
others--the numerous sensory hairs touching the surface--are more responsive to
compressional waves,” according to Brownell and van Hemmen, 2000.

Interest/Importance:
Only the Arizona species (Centruroides)
has venom strong enough to be lethal or cause “severe local skin reaction,
neurologic collapse, respiratory collapse, cardiovascular collapse, respiratory
failure, [or] cardiovascular failure”, according to eMedicine. Anti-venom from ASU is not CDC approved; Instituto
Bioclon of Mexico trials under way in 2004.Otherwise, scorpion venom has pharmacological utility in VGSC, cystic
fibrosis, or novel drug delivery pathways.

Number of Species:
Worldwide, about 1300; North American, about 90 (“Southern Nevada, southeastern
California, and central Arizona with highest diversity,” Polis and Sissom, 1990);
and only 25-50 dangerous to humans and all are in the Buthidae family.

Ancestry:“the only land animals with a fossil record stretching
back to the colonization of land by aquatic animals,” according to Polis and
Sissom, 1990.

Range: Southwestern
US; north into British Columbia; Virginia, Kentucky and Missouri; and northern
Florida.

Did You Know: The
scorpion is the only insect in the Zodiac or that UV fluorescence of scorpions
was first reported in 1954?According to
Walter Reed, “The [bright blue-green] fluorescence is caused by an unidentified
substance [hypothesized by Fasel et al. as a flavin or flavone and confirmed by
Wankhede, 2004 as beta carboline, a neuroprotective, and
7-hydroxy-4-methylcoumarin which is used as an optical brightener] in a very
thin layer in the cuticle of the scorpion called the hyaline layer.Newly molted scorpions do not fluoresce.As the new cuticle hardens, the fluorescent
quality increases. This [condition] indicates
that the fluorescent factor is either secreted by the scorpion shortly after
molting or that the fluorescence is a by-product of the tanning process. Alcohol in which scorpions have been preserved
may also fluoresce. The hyaline layer of
the cuticle is very tough stuff. It is
often found in scorpion fossils.Even
after hundreds of millions of years, while all the other layers of the cuticle
have been lost, this hyaline layer remains embedded in fossil rocks. And yes,
it still fluoresces. Nobody knows the
function of the hyaline cuticle or its strange fluorescence. Some have suggested that it serves as UV
sensor (all scorpions are basically nocturnal and shun the light).”